I forget the terminology but it has two buttons: artwork and something else (code? ui?)

Extract the "something else" and it will put the FrameXML folder and all its files in your Interface folder. Then you can read them. The health/mana bars come from PlayerFrame, PartyFrame (see PartyFrameTemplates.xml) and TargetFrame.

If you open PlayerFrame.xml you'll find PlayerFrameHealthBar about 2/3 the way down.

hehe I did install that firefox plugin for IRC client someone posted on the wow forums. Even registered my name on freenode. But I'm too busy crashing my client right now lol I'll see if I get time later tonight.